Should I accept my admission into Sophia University in Tokyo, Japan?

Japan is safe. Tokyo is safe. It is perfectly fine for you to go to Japan and you really should not avoid it because of the earthquake. There is nothing to worry about and all the foreigners "abandoning ship" with Japan is not helping their already-bad economy improve. And since I assume you will be going in the fall or at least summer (since you mentioned you have a few months left) everything will be returning very close to normal once again. As is, life in Tokyo already is pretty normal again.